P2p tcp nat schematic + Source Code (original), p2pnat

P2p tcp nat schematic + Source Code (original), p2pnat

Currently, p2p udp nat penetration articles on the Internet are numerous, and there are few p2p tcp nat articles. After several days of study, I have finally learned something about it. I would like to share it with you. Thank you for your support!

 

1. First, you must have an internet server or a telecom carrier to support the forwarding of the router (the specific process is not detailed, please Baidu)

2. A computer that can access the Internet (the computer in the Intranet is meaningless)

 

The core code is:

socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);

The function is to enable the connected port to listen again to achieve the purpose of tcp nat

Schematic:

Internet server code (ps: up the Master cannot afford to buy a server and can only use the company's router for forwarding, please forgive me !) :

Using System; using System. collections. generic; using System. linq; using System. net; using System. net. sockets; using System. text; using System. threading; namespace TcpNatTestS {class Program {public static IPAddress GetLocalIP () {try {string HostName = Dns. getHostName (); // obtain the host name IPHostEntry IpEntry = Dns. getHostEntry (HostName); for (int I = 0; I <IpEntry. addressList. length; I ++) {// filter IPv4 IP addresses from the IP address list // AddressFamily. interNetwork indicates that the IP address is IPv4, // AddressFamily. interNetworkV6 indicates that this address is of the IPv6 Type if (IpEntry. addressList [I]. addressFamily = AddressFamily. interNetwork) {return IpEntry. addressList [I] ;}} return IPAddress. any;} catch (Exception ex) {return IPAddress. any ;}} static void Main (string [] args) {TcpListener tcp = new TcpListener (new IPEndPoint (GetLocalIP (), 8085); tcp. start (); new Thread (e => {while (true) {var lianjie = tcp. acceptTcpClient (); // new TcpClient (). connect (IPEndPoint) lianjie. client. remoteEndPoint); lianjie. client. send (UnicodeEncoding. unicode. getBytes ("your Internet ip address is:" + lianjie. client. remoteEndPoint); Console. writeLine ("intranet server: local port:" + lianjie. client. localEndPoint + "remote port:" + lianjie. client. remoteEndPoint );}}). start (); Console. readKey ();}}}

 

Intranet client (you need to enter the ip address of the internet server ):

 

Using System; using System. collections. generic; using System. linq; using System. net; using System. net. sockets; using System. text; using System. threading; namespace TcpNatTestA {class Program {public static IPAddress GetLocalIP () {try {string HostName = Dns. getHostName (); // obtain the host name IPHostEntry IpEntry = Dns. getHostEntry (HostName); for (int I = 0; I <IpEntry. addressList. length; I ++) {// filter IPv4 IP addresses from the IP address list // AddressFamily. interNetwork indicates that the IP address is IPv4, // AddressFamily. interNetworkV6 indicates that this address is of the IPv6 Type if (IpEntry. addressList [I]. addressFamily = AddressFamily. interNetwork) {return IpEntry. addressList [I] ;}} return IPAddress. any;} catch (Exception ex) {return IPAddress. any ;}} static void Main (string [] args) {new Thread (e =>{ TcpClient clinet = new TcpClient (); clinet. client. setSocketOption (SocketOptionLevel. socket, SocketOptionName. reuseAddress, true); var bendi = new IPEndPoint (GetLocalIP (), 7896); clinet. client. bind (bendi); clinet. connect (new IPEndPoint (IPAddress. parse ("Enter your server ip Address"), 8085); TcpListener tcp = new TcpListener (bendi); tcp. server. setSocketOption (SocketOptionLevel. socket, SocketOptionName. reuseAddress, true); tcp. start (); new Thread () => {while (true) {var jiqi = tcp. acceptTcpClient (); Console. writeLine ("intranet client: Local endpoint:" + bendi + "remote endpoint:" + jiqi. client. remoteEndPoint );}}). start (); clinet. client. send (UnicodeEncoding. unicode. getBytes ("Haha"); byte [] hh = new byte [500]; var weishu = clinet. client. receive (hh); byte [] temp = new byte [weishu]; Array. copy (hh, temp, weishu); // Console. writeLine ("remote port:" + clinet. client. remoteEndPoint); Console. writeLine (UnicodeEncoding. unicode. getString (temp ));}). start (); Console. readKey ();}}}

 

 

If you have any questions, contact me.